Tissue Viscoelasticity Research Articles

Comprehensive experimental assessments of rheological models’ performance in elastography of soft tissues

Elastography researchers have utilized several rheological models to characterize soft tissue viscoelasticity over the past thirty years. Due to the frequency-dependent behavior of viscoelastic parameters as well as the different techniques and frequencies employed in various studies of soft tissues, rheological models have value in standardizing disparate techniques via explicit mathematical representations. However, the important question remains: which of the several available models should be considered for widespread adoption within a theoretical framework? We address this by evaluating the performance of three well established rheological models to characterize ex vivo bovine liver tissues: the Kelvin-Voigt (KV) model as a 2-parameter model, and the standard linear solid (SLS) and Kelvin-Voigt fractional derivative (KVFD) models as 3-parameter models. The assessments were based on the analysis of time domain behavior (using stress relaxation tests) and frequency domain behavior (by measuring shear wave speed (SWS) dispersion). SWS was measured over a wide range of frequency from 1 Hz to 1 kHz using three different tests: (i) harmonic shear tests using a rheometer, (ii) reverberant shear wave (RSW) ultrasound elastography scans, and (iii) RSW optical coherence elastography scans, with each test targeting a distinct frequency range. Our results demonstrated that the KVFD model produces the only mutually consistent rendering of time and frequency domain data for liver. Furthermore, it reduces to a 2-parameter model for liver (correspondingly to a 2-parameter “spring-pot” or power-law model for SWS dispersion) and provides the most accurate predictions of the material viscoelastic behavior in time (>98% accuracy) and frequency (>96% accuracy) domains. Statement of SignificanceRheological models are applied in quantifying tissues viscoelastic properties. This study is unique in presenting comprehensive assessments of rheological models:•We employed experimental data in both the frequency domain (shear wave speed (SWS) vs. frequency) and time domain (stress relaxation) to assess rheological models’ performances.•SWS were acquired over a wide frequency range, 1 Hz to 1 kHz, by three independent techniques.•Using the frequency domain analysis, we evaluated how well each model can predict measured time domain behaviors (and vice versa).•This presents wide-ranging experimental proofs as the most comprehensive study of its type in terms of the number of experiments, frequency range, and conjoined assessments of time and frequency domains behaviors, demonstrating the most appropriate rheological model for soft tissues.

Stress relaxation behavior of left ventricular myocardium in mice

BackgroundMyocardial tissues are known to exhibit viscoelastic behavior, i.e., the myocardial wall stress is gradually decaying when stretched at a constant level, referred to as stress relaxation behavior. The study of this behavior becomes important in structural heart diseases, where both passive and active relaxation behaviors of the myocardium may alter. As myocardial tissues display a complex, 3D micro‐architecture, the anisotropy of stress relaxation remains understudied. Our objective in this study was to investigate the anisotropy of (passive) stress relaxation behavior of the left ventricular (LV) myocardium in healthy small animals.MethodsWe used biaxial stress relaxation tests in wild‐type murine specimens (n=2). Full‐thickness myocardium LV free wall (LVFW) specimens were isolated from the mouse hearts (Fig. 1a), with the slab edges being aligned with the longitudinal (apex‐to‐outflow‐tract), circumferential, and radial directions of the LV. The specimens were mounted in a biaxial mechanical testing machine along the circumferential and longitudinal directions. The specimens were stretched in three different loading protocols with circumferential‐to‐longitudinal strain ratios of 30:30, 15:30, and 30:15%. The samples were loaded to the peak strain at a rate of 0.01 s‐1 and held at this stretch for 10 minutes to allow the relaxation. The time‐varying stress was recorded. We used an exponential decay fit to estimate the stress relaxation time constants in both directions.ResultsStress relaxation time constants showed noticeable differences between multiple loading ratios with equibiaxial loading (30:30) having the largest relaxation time constant followed by the circumferential stress in the 30:15 ratio (Fig. 1b). The larger strains led to larger stress relaxation constants (Fig. 1b‐c) indicating a strain‐dependent viscoelastic behavior. The quasi‐static equibiaxial loading of the same specimens resulted in a nearly isotropic behavior (not shown here), exhibiting insignificant contrast between the stresses in the circumferential and longitudinal directions. Interestingly, the contrast in the relaxation behavior between the circumferential and longitudinal directions were similarly insignificant (Fig. 1b). Non‐equibiaxial loadings (15:30 and 13:50) showed significantly faster relaxation for the direction with smaller strains (Fig. 1b).ConclusionsMyocardial tissue viscoelasticity is an important behavior contributing to both diastolic and systolic cardiac function, which remains understudied, especially in case of structural heart diseases associated with impaired relaxation in the LV. Our study suggests that stress relaxation behavior is prominent in the LV myocardium and may exhibit different relaxation behavior depending on strain magnitudes and strain ratios along different directions. The level of anisotropy in stress relaxation was found to be similar to the level of anisotropy in the tissue quasi‐static behavior. These results serve to motivate further studies to fully characterize the viscoelastic behavior of LV myocardium and its contribution to the LV relaxation and filling in murine models of LV diseases.

Mechanical Response of Mouse Cervices Lacking Decorin and Biglycan During Pregnancy.

Cervical remodeling is critical for a healthy pregnancy. The proper regulation of extracellular matrix (ECM) turnover leads to remodeling throughout gestation, transforming the tissue from a stiff material to a compliant, extensible, viscoelastic tissue prepared for delivery. Small leucine-rich proteoglycans (SLRPs) regulate structural fiber assembly in the cervical ECM and overall tissue material properties. To quantify the SLRPs' mechanical role in the cervix, whole cervix specimens from nonpregnant and late pregnant knockout mice of SLRPs, decorin and biglycan, were subjected to cyclic load-unload, ramp-hold, and load-to-failure mechanical tests. Further, a fiber composite material model, accounting for collagen fiber bundle waviness, was developed to describe the cervix's three-dimensional large deformation equilibrium behavior. In nonpregnant tissue, SLRP knockout cervices have the same equilibrium material properties as wild-type tissue. In contrast, the load-to-failure and ramp-hold tests reveal SLRPs impact rupture and time-dependent relaxation behavior. Loss of decorin in nonpregnant (NP) cervices results in inferior rupture properties. After extensive remodeling, cervical strength is similar between all genotypes, but the SLRP-deficient tissue has a diminished ability to dissipate stress during a ramp-hold. In mice with a combined loss of decorin and biglycan, the pregnant cervix loses its extensibility, compliance, and viscoelasticity. These results suggest that decorin and biglycan are necessary for crucial extensibility and viscoelastic material properties of a healthy, remodeled pregnant cervix.

Enhancing cavitation dynamics and its mechanical effects with dual-frequency ultrasound

Objective. Acoustic cavitation and its mechanical effects (e.g. stress and strain) play a primary role in ultrasound applications. Introducing encapsulated microbubbles as cavitation nuclei and utilizing dual-frequency ultrasound excitation are highly effective approaches to reduce cavitation thresholds and enhance cavitation effects. However, the cavitation dynamics of encapsulated microbubbles and the resultant stress/strain in viscoelastic tissues under dual-frequency excitation are poorly understood, especially for the enhancement effects caused by a dual-frequency approach. The goal of this study was to numerically investigate the dynamics of a lipid-coated microbubble and the spatiotemporal distributions of the stress and strain under dual-frequency excitation. Approach. The Gilmore–Zener bubble model was coupled with a shell model for the nonlinear changes of both shell elasticity and viscosity to accurately simulate the cavitation dynamics of lipid-coated microbubbles in viscoelastic tissues. Then, the spatiotemporal evolutions of the cavitation-induced stress and strain in the surrounding tissues were characterized quantitatively. Finally, the influences of some paramount parameters were examined to optimize the outcomes. Main results. We demonstrated that the cavitation dynamics and associated stress/strain were prominently enhanced by a dual-frequency excitation, highlighting positive correlations between the maximum bubble expansion and the maximum stress/strain. Moreover, the results showed that the dual-frequency ultrasound with smaller differences in its frequencies and pressure amplitudes could enhance the bubble oscillations and stress/strain more efficiently, whereas the phase difference manifested small influences under these conditions. Additionally, the dual-frequency approach seemed to show a stronger enhancement effect with the shell/tissue viscoelasticity increasing to a certain extent. Significance. This study might contribute to optimizing the dual-frequency operation in terms of cavitation dynamics and its mechanical effects for high-efficient ultrasound applications.

Growth of lipid-coated multi-microbubbles in viscoelastic tissues

Growth of lipid-coated multi-microbubbles in viscoelastic tissues

Assessment of selected muscles reactivity in the lower spinal segment

Background: Lumbar spine pain is now a common affliction. In 90% of cases, the pain is of ambiguous and multicausal etiology, described as non-specific lower back pain (NLBP). Various models of this dysfunction were examined. The most popular model presents the pain as a result of an insult and secondary to changes in tension and lumbar muscles degeneration. There is no unequivocal solution concerning the cause of lumbar spine pain in the literature. Aim of the study: To examine the differences in muscles reactivity in the lumbar region in cases who suffer from lumbar spine pain in comparison to otherwise healthy controls. Material and methods: In total, 50 participants (24 men and 26 women) aged 18–45, including 24 people with pain, and 26 without ailments were included in the study. The visual analogue scale was used to measure pain intensity. The participants were assessed to determine the reactivity of the soft tissues of the lumbar part of the body. Selected muscles of this area were examined using a myotonometer, which shows five parameters relevant to viscoelastic tissues. Results: There were significant differences in the level of the pain (p<0.001), hypokinesia of the left abdominal rectus (p<0.05), asymmetry indicators for the creep parameter of the erector spinalis and abdominal external oblique muscle, and the stiffness of abdominal rectus (p<0.05). No significant differences for the remaining parameters were found. Conclusions: Tissue reactivity of selected muscles of the lumbar spine shows slight differences because of pain afflictions occurring in this area.

Improved two-point frequency shift power method for measurement of shear wave attenuation

Quantitative assessment of mechanical properties of biological soft tissues is frequently evaluated using a noninvasive modality, called ultrasound shear wave elastography (SWE). SWE typically exerts an acoustic radiation force (ARF) to produce shear waves propagating in the lateral direction for which velocities and attenuations are measured. The tissue viscoelasticity is commonly studied by investigating the shear wave phase velocity curves. Viscoelastic tissue properties can also be characterized through utilizing various shear wave attenuation techniques. In this study, we propose an improved method for measuring the shear wave attenuation, called two-point frequency shift power (2P-FSP), which is an improved version of the two-point frequency shift (2P-FS) method. The technique is fully data driven and does not use a rheological model for mathematical modeling. The 2P-FSP method utilizes the power spectra frequency shift of shear waves measured at two spatial positions, which provides robustness to noise. The conceptual basis for the 2P-FSP is provided and tested with numerical and experimental data. We investigated how the location of the first signal and the distance interval between the two locations influence the shear wave attenuation measurement in the 2P-FSP technique. We utilized the 2P-FSP method on numerical phantom data generated using a finite-difference-based method in tissue-mimicking viscoelastic media. Moreover, we tested the 2P-FSP method with data from custom-made tissue-mimicking viscoelastic phantom experiments, and ex vivo porcine liver. We compared results from the proposed technique with results from 2P-FS and analytical values in the case of simulations. The results showed that the 2P-FSP method provides improved results over the 2P-FS technique for lower signal-to-noise ratio (SNR) and locations farther from the push location considered, and can be used to measure attenuation of viscoelastic soft tissues.

Temperature evolution following joint loading promotes chondrogenesis by synergistic cues via calcium signaling

During loading of viscoelastic tissues, part of the mechanical energy is transformed into heat that can locally increase the tissue temperature, a phenomenon known as self-heating. In the framework of mechanobiology, it has been accepted that cells react and adapt to mechanical stimuli. However, the cellular effect of temperature increase as a by-product of loading has been widely neglected. In this work, we focused on cartilage self-heating to present a 'thermo-mechanobiological' paradigm, and demonstrate how the coupling of a biomimetic temperature evolution and mechanical loading could influence cell behavior. We thereby developed a customized in vitro system allowing to recapitulate pertinent in vivo physical cues and determined the cells chondrogenic response to thermal and/or mechanical stimuli. Cellular mechanisms of action and potential signaling pathways of thermo-mechanotransduction process were also investigated. We found that co-existence of thermo-mechanical cues had a superior effect on chondrogenic gene expression compared to either signal alone. Specifically, the expression of Sox9 was significantly upregulated by application of the physiological thermo-mechanical stimulus. Multimodal transient receptor potential vanilloid 4 (TRPV4) channels were identified as key mediators of thermo-mechanotransduction process, which becomes ineffective without external calcium sources. We also observed that the isolated temperature evolution, as a by-product of loading, is a contributing factor to the cell response and this could be considered as important as the conventional mechanical loading. Providing an optimal thermo-mechanical environment by synergy of heat and loading portrays new opportunity for development of novel treatments for cartilage regeneration and can furthermore signal key elements for emerging cell-based therapies.

MyotonPro Is a Valid Device for Assessing Wrist Biomechanical Stiffness in Healthy Young Adults.

BackgroundThe MyotonPro is a portable device for measuring biomechanical and viscoelastic properties in superficial soft tissues. The aims of this study are firstly to validate the MyotonPro compared to a reliable gold-standard frame and secondly to observe the influence of MyotonPro measurement on the total wrist viscoelasticity.MethodsThree silicone polymers with different elastic properties were assessed with the MyotonPro and with a reference rheometer (Universal Tribometer Mod). Then, a free oscillations method was used to measure the passive elastic and viscous stiffness of the wrist and compared to MyotonPro forearm measurements.ResultsA one-way ANOVA demonstrated the validity of the MyotonPro's stiffness (p = 0.001), decrement (p < 0.001), and relaxation (p = 0.008) parameters for measuring the elastic stiffness (k) of the three polymers. The MyotonPro parameters demonstrated excellent reliability on the forearm. Proximal and distal anterior myofascial measurements of the MyotonPro were moderately correlated to the elastic stiffness (p = 0.0027–0.0275, absolute r = from 0.270 to 0.375) of the wrist while the postero-distal myofascial tissues of the forearm demonstrated a moderate correlation with the viscous stiffness of the wrist (p = 0.0096–0.0433, absolute r = from 0.257 to 0.326).DiscussionThe MyotonPro is a valid device for measuring elastic stiffness as well as a portable, affordable, and easy-to-use tool for quantifying the biomechanical properties and viscoelasticity of myofascial tissue in healthy subjects.

Viscoelasticity, Like Forces, Plays a Role in Mechanotransduction.

Viscoelasticity and its alteration in time and space has turned out to act as a key element in fundamental biological processes in living systems, such as morphogenesis and motility. Based on experimental and theoretical findings it can be proposed that viscoelasticity of cells, spheroids and tissues seems to be a collective characteristic that demands macromolecular, intracellular component and intercellular interactions. A major challenge is to couple the alterations in the macroscopic structural or material characteristics of cells, spheroids and tissues, such as cell and tissue phase transitions, to the microscopic interferences of their elements. Therefore, the biophysical technologies need to be improved, advanced and connected to classical biological assays. In this review, the viscoelastic nature of cytoskeletal, extracellular and cellular networks is presented and discussed. Viscoelasticity is conceptualized as a major contributor to cell migration and invasion and it is discussed whether it can serve as a biomarker for the cells’ migratory capacity in several biological contexts. It can be hypothesized that the statistical mechanics of intra- and extracellular networks may be applied in the future as a powerful tool to explore quantitatively the biomechanical foundation of viscoelasticity over a broad range of time and length scales. Finally, the importance of the cellular viscoelasticity is illustrated in identifying and characterizing multiple disorders, such as cancer, tissue injuries, acute or chronic inflammations or fibrotic diseases.

Thermomechanical interactions in viscoelastic skin tissue under different theories

Thermomechanical interactions in viscoelastic skin tissue under different theories

Investigating the heterogeneity of viscoelastic properties in prostate cancer using MR elastography at 9.4T in fresh prostatectomy specimens

PurposeTo quantify the heterogeneity of viscoelastic tissue properties in prostatectomy specimens from men with prostate cancer (PC) using MR elastography (MRE) with histopathology as reference. MethodsTwelve fresh prostatectomy specimens were examined in a preclinical 9.4T MRI scanner. Maps of the complex shear modulus (|G*| in kPa) with its real and imaginary part (G' and G" in kPa) were calculated at 500 Hz. Prostates were divided into 12 segments for segment-wise measurement of viscoelastic properties and histopathology. Coefficients of variation (CVs in %) were calculated for quantification of heterogeneity. ResultsGroup-averaged values of cancerous vs. benign segments were significantly increased: |G*| of 12.13 kPa vs. 6.14 kPa, G' of 10.84 kPa vs. 5.44 kPa and G" of 5.45 kPa vs. 2.92 kPa, all p < 0.001. In contrast, CVs were significantly increased for benign segments: 23.59% vs. 26.32% (p = 0.014) for |G*|, 27.05% vs. 37.84% (p < 0.003) for G', and 36.51% vs. 50.37% (p = 0.008) for G". DiscussionPC is characterized by a stiff yet homogeneous biomechanical signature, which may be due to the unique nondestructive growth pattern of PC with intervening stroma, providing a rigid scaffold in the affected area. In turn, increased heterogeneity in benign prostate segments may be attributable to the presence of different prostate zones with involvement by specific nonmalignant pathology.

Analysis of surgical needle insertion modeling and viscoelastic tissue material interaction for minimally invasive surgery (MIS)

Soft tissue modeling of surgical events is essential for both considering tissue reactions to surgical instrumentation, in addition, to conducting the design of the surgical instrument. Mainly with observes to surgical needle insertion for minimally invasive surgery (MIS) into soft biological tissue, one of the regularly performed surgical events, many works have been prepared in references to modeling how surgical needles insert the soft biological tissue material as they pass through in the direction of objects deep inside the living body. Deformation of biological soft tissue is one of the important issues, which impacts the surgical needle insert inside the living soft viscoelastic tissue. A needle insertion model is presented to calculate the insertion forces and tissue deformation phenomenon. The experimentations are done on the tissue mimic gel specimens, and the surgical needle insertion-based model for the deformation phenomenon is analyzed to investigate the force model, frictional stress and deflection phenomenon. This study can help to investigate the needle insertion process for analyzing the effect of the surgical needle insertion, which could advance the enactment of several surgical needle insertion-based procedures such as minimally invasive surgery (MIS) and brachytherapy.

The behavior of motoneurons.

Eye movements occur when motor neurons (cranial nerves III, IV and VI) discharge and cause contractions of the extraocular muscles. Movements of the eye are influenced by several main factors: the force generated in each muscle, the inertia of the globe, the viscous and elastic properties of the muscles, and the viscoelasticity of the suspensory orbital tissues (all of which constitute the oculomotor plant). Overall, the response of the plant is sluggish, so the innervation to the muscles must have a specific time-course of activation. Otherwise, the movements of the eye would be too slow and would lead to smearing of images across the retina. Differential equations are derived that describe the activity in motoneurons and the response of the plant.

Gpu-Accelerated Study of the Inertial Cavitation Threshold in Viscoelastic Soft Tissue Using a Dual-Frequency Driving Signal

Gpu-Accelerated Study of the Inertial Cavitation Threshold in Viscoelastic Soft Tissue Using a Dual-Frequency Driving Signal

GPU-Accelerated Study of the Inertial Cavitation Threshold in Viscoelastic Soft Tissue Using a Dual-Frequency Driving Signal

GPU-Accelerated Study of the Inertial Cavitation Threshold in Viscoelastic Soft Tissue Using a Dual-Frequency Driving Signal

Influence of Viscoelasticity on Dynamic Fatiguing Behavior of Muscle Using Myotonometry and Surface Electromyography Measurements

In this work, an attempt has been made to analyse the influence of tissue viscoelasticity on the fatiguing behaviour of skeletal muscle. For this purpose, myotonometry and surface electromyography (sEMG) signals are recorded from the biceps brachii muscle of adult volunteers. Viscoelastic characterization of muscle is carried out using two parameters, namely Dynamic Stiffness (DS) and Relaxation Time (RT) which are computed from the myotonometry signal. Fatiguing contraction is characterized using Time to Task Failure (TTF) and Mean Absolute Value (MAV) extracted from the surface electromyography signal. Linear regression is performed to find the association between myotonometric parameters and TTF. Results show that the TTF values are comparable between both hands, but the values are higher in the dominant hand. Linear relationship between myotonometric parameters and TTF is observed with adjusted R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> > 30% for the dominant hand, and adjusted R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> > 40% for the non-dominant hand. Further, there is variation in the myotonometric parameters between non-fatigue and fatigue states. Similarly, MAV is also noted to increase from non-fatigue to fatigue state. Percentage variation of RT from non-fatigue to fatigue is linearly correlated with average MAV values. The results indicate that viscoelastic properties of muscle along with myoelectrical features can provide better characterization of fatiguing contraction in skeletal muscle, and could be helpful in the domain of sports medicine and rehabilitative design.

Nonlinear Characterization of Tissue Viscoelasticity With Acoustoelastic Attenuation of Shear Waves.

Shear-wave elastography (SWE) measures shear-wave speed (SWS), which is related to the underlying shear modulus of soft tissue. SWS in soft tissue changes depending on the amount of external strain that soft tissue is subjected to due to the acoustoelastic (AE) phenomenon. In the literature, variations of SWS as a function of applied uniaxial strain were used for nonlinear characterization, assuming soft tissues to be elastic, although soft tissues are indeed viscoelastic in nature. Hence, nonlinear characterization using SWS alone is insufficient. In this work, we use SWS together with shear-wave attenuation (SWA) during incremental quasi-static compressions in order to derive biomechanical characterization based on the AE theory in terms of well-defined storage and loss moduli. As part of this study, we also quantify the effect of applied strain on measurements of SWS and SWA since such confounding effects need to be taken into account when using SWS and/or SWA, e.g., for staging a disease state, while such effects can also serve as an additional imaging biomarker. Our results from tissue-mimicking phantoms with varying oil percentages and ex vivo porcine liver experiments demonstrate the feasibility of our proposed methods. In both experiments, SWA was observed to decrease with applied strain. For 10% compression in ex vivo livers, shear-wave attenuation decreased, on average, by 28% (93 Np/m), while SWS increased, on average, by 20% (0.26 m/s).

Characterizing and Engineering Biomimetic Materials for Viscoelastic Mechanotransduction Studies.

The mechanical behavior of soft tissue extracellular matrix is time dependent. Moreover, it evolves over time due to physiological processes as well as aging and disease. Measuring and quantifying the time-dependent mechanical behavior of soft tissues and materials pose a challenge, not only because of their labile and hydrated nature but also because of the lack of a common definition of terms and understanding of models for characterizing viscoelasticity. Here, we review the most important measurement techniques and models used to determine the viscoelastic properties of soft hydrated materials—or hydrogels—underlining the difference between viscoelastic behavior and the properties and descriptors used to quantify viscoelasticity. We then discuss the principal factors, which determine tissue viscoelasticity in vivo and summarize what we currently know about cell response to time-dependent materials, outlining fundamental factors that have to be considered when interpreting results. Particular attention is given to the relationship between the different time scales involved (mechanical, cellular and observation time scales), as well as scaling principles, all of which must be considered when designing viscoelastic materials and performing experiments for biomechanics or mechanobiology applications. From this overview, key considerations and directions for furthering insights and applications in the emergent field of cell viscoelastic mechanotransduction are provided.Impact statementOur tissues are viscoelastic: they respond to mechanical stresses and strains in a time-dependent manner. Their mechanical behavior also evolves over time due to growth, aging, remodeling and disease. Understanding cell response to time-dependent and time-evolving mechanical cues is important for a better comprehension of a wide number of pathophysiological processes and for the design of biomimetic substrates, which can be used as physiologically relevant in vitro models and in regenerative medicine applications. This review highlights the importance of a more rigorous approach toward viscoelastic material design and testing for cell mechanobiology studies, which embrace the entire spectrum of elasto- and viscotransduction.

Tissue fluidity mediated by adherens junction dynamics promotes planar cell polarity-driven ommatidial rotation

The phenomenon of tissue fluidity—cells’ ability to rearrange relative to each other in confluent tissues—has been linked to several morphogenetic processes and diseases, yet few molecular regulators of tissue fluidity are known. Ommatidial rotation (OR), directed by planar cell polarity signaling, occurs during Drosophila eye morphogenesis and shares many features with polarized cellular migration in vertebrates. We utilize in vivo live imaging analysis tools to quantify dynamic cellular morphologies during OR, revealing that OR is driven autonomously by ommatidial cell clusters rotating in successive pulses within a permissive substrate. Through analysis of a rotation-specific nemo mutant, we demonstrate that precise regulation of junctional E-cadherin levels is critical for modulating the mechanical properties of the tissue to allow rotation to progress. Our study defines Nemo as a molecular tool to induce a transition from solid-like tissues to more viscoelastic tissues broadening our molecular understanding of tissue fluidity.